The Government's plans to clamp down on zero hour contracts and extend paid parental leave hang in the balance after its support partners told Workplace Relations Minister Michael Woodhouse they won't support it unless serious changes are made.

The Employment Standards Bill is due back before parliament this week – and needs to be passed in the next few weeks so the extension to 18 weeks paid parental leave can come into force on April 1, as promised.

Unions and opposition parties last year put pressure on Mr Woodhouse to scrap the so called zero hour contracts.

And while Mr Woodhouse had promised to abolish the worst parts of those contracts, there are two main sticking points on the bill that mean that as it stands the Government doesn't have the numbers to pass it.

National thought they could finesse their way out of this with spin and bullshit, by announcing a "ban" which was nothing of the sort. I guess they hadn't counted on their support partners holding them to their word. Its a reminder of the value of MMP; if National had had an artificial majority under FPP, they wouldn't have felt the need to even legislate, let alone be able to be forced to keep their promises.

The good news is that everyone wants this bill to pass - and with a majority to fix it whether or not the government wants to, National will be eager to make a deal to avoid losing control. But its a humiliating defeat for them, and a signal that their "PR instead of policy" strategy has some limits.